Partially coherent lensless holographic microscopy with micrometre resolution applied to extended objects

摘要

In this work, a blue light-emitting diode (LED) is used in lenseless Digital In-line Holography Microscopy (DIHM) to show that micrometre resolution can be reached even when millimetre range objects, such as the head of a fruit fly, are imaged with partially coherent spherical wavefronts. The influence of the spatial coherence on the resolution of the microscope is analysed by changing the diameter of pinhole from which the spherical wavefronts are originated. Even though the best achieved resolution with the use of the LED is less than the ultimate provided by the use of fully coherent laser sources, the former is very competitive as the ratio performance/cost is compared for both approaches. Micrometre-sized beads are used for quantitative testing of the lateral resolution.